In some cases, Cassandra nodes can consume significantly more disk space than reported as loaded data. For this reason, it is important to keep an eye on the raw disk usage on your nodes as well as the volume of loaded data.
Instaclustr reports this information in our console monitoring page as described here: https://support.instaclustr.com/hc/en-us/articles/206608448-Disk-Usage
We strongly recommend maintaining a minimum of 30% free disk space in normal operations. This is to ensure there is sufficient available space for Cassandra to performance operations such as compaction which temporarily consume additional disk space.
If your cluster is simply filling up with data then it can be easily scaled out by adding additional nodes. To do this, use the add node feature on our console or contact email@example.com for assistance.